Multi-partitioning of memories

ABSTRACT

Various embodiments comprise apparatuses and methods including a method of reconfiguring partitions in a memory device as directed by a host. The method includes managing commands through a first interface controller to mapped portions of a first memory not having an attribute enhanced set, and mapping portions of a second memory having the attribute enhanced set through a second interface controller. Additional apparatuses and methods are described.

PRIORITY APPLICATION

This application is a continuation of U.S. application Ser. No.12/628,152, filed Nov. 30, 2009, now U.S. Pat. No. 8,307,151 which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The requirements of increasing functionality, shrinking physical sizeand reducing overall system cost can place system constraints onconsumer electronics devices. Flash memory has been used to make storageportable among consumer devices such as car navigation systems, smartphones, digital cameras, PDAs, and MP3 players, and countless otherportable applications. New non-volatile technologies that supplementflash memory are being planned for an increasing number of functions indigital consumer devices. These new non-volatile memories provide“managed memory” capabilities that allow system designers to re-evaluatethe memory subsystems and look for improvements in these devices.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter regarded as the invention is particularly pointed outand distinctly claimed in the concluding portion of the specification.The invention, however, both as to organization and method of operation,together with objects, features, and advantages thereof, may best beunderstood by reference to the following detailed description when readwith the accompanying drawings in which:

FIGS. 1 and 2 illustrate an organization of the addressable space in thememory areas of a memory combination, with FIG. 1 showing theorganization before partitioning and FIG. 2 showing the organizationafter partitioning in accordance with the present invention;

FIG. 3 illustrates an architecture having a bus common with twocontrollers, one for MLC NAND Flash and another for Phase-Change Memory(PCM) to provide memory partitioning;

FIG. 4 illustrates an architecture that includes the host coupled via abus to a controller that is connected to MLC NAND Flash, with thecontroller connecting to another controller for the PCM; and

FIG. 5 illustrates an architecture that includes a bus coupling the hostto one controller that is connected to both the MLC NAND Flash and thePCM.

It will be appreciated that for simplicity and clarity of illustration,elements illustrated in the figures have not necessarily been drawn toscale. For example, the dimensions of some of the elements may beexaggerated relative to other elements for clarity. Further, whereconsidered appropriate, reference numerals have been repeated among thefigures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the invention.However, it will be understood by those skilled in the art that thepresent invention may be practiced without these specific details. Inother instances, well-known methods, procedures, components and circuitshave not been described in detail so as not to obscure the presentinvention.

Use of the terms “coupled” and “connected”, along with theirderivatives, may be used. It should be understood that these terms arenot intended as synonyms for each other. Rather, in particularembodiments, “connected” may be used to indicate that two or moreelements are in direct physical or electrical contact with each other.“Coupled” may be used to indicated that two or more elements are ineither direct or indirect (with other intervening elements between them)physical or electrical contact with each other, and/or that the two ormore elements co-operate or interact with each other (e.g. as in a causeand effect relationship).

Current and future versions of embedded MultiMediaCard (MMC) standardspecifications include partitioning features of the logical addressablespace in a managed memory device. Partitioning the logical addressablespace of nonvolatile memory permits the upper software layers which makeuse of the nonvolatile media to segment the available memory space tostore different types of data or code. By further including Phase-ChangeMemory (PCM) as the nonvolatile memory in managed memory applications,features are provided that add quick adaptability to functionalitiesrelated to the device configurability by the host application inpartitioning the addressable space.

FIGS. 1 and 2 illustrate an organization of the embedded MultiMediaCardaddressable space, with FIG. 1 showing an organization 114 beforepartitioning and FIG. 2 showing an organization 214 after partitioning.Referring to FIG. 1, the embedded MultiMediaCard has an abstractedinterface which allows the host to initially access a Boot Partition(BOOT 1) 102; a Boot Partition (BOOT 2) 104; a Replay Protected MemoryBlock partition (RPMB) 106; and a User Data Area 108. The two bootareas, i.e., Boot Partition 102 and Boot Partition 104, are used tostore the system boot code that is downloaded at every power cycle usinga standardized procedure. Replay Protected Memory Block Partition 106 isused to store the pieces of data and sensitive information that areprotected by a security algorithm. User Data Area 108 is used to storedata that may be accessed by MMC protocol commands.

At application level both Boot Partitions (BOOT1, BOOT2) 102, 104 andReplay Protected Memory Block partition (RPMB) 106, are required to bereliable. By including a Phase-Change Memory (PCM) in the embeddedMultiMediaCard it is possible to map the Boot Partitions (BOOT1, BOOT2)102,104 and Replay Protected Memory Block partition (RPMB) 106 to thePhase-Change Memory Array. This may be implemented as a defaultconfiguration, and in this case, the address space organization 114before partitioning indicates this mapping.

FIG. 2 shows the available memory space of the reconfigured embeddedMultiMediaCard. As shown by the figure and in accordance with featuresof the present invention, the memory may be configured during thelifecycle of the memory to obtain boot areas 202 and 204, i.e., Boot 1and Boot 2, a Replay Protected Memory Block (RPMB) 206, a Main User DataArea 208, and up to four General Purpose partitions 212, 214, 216, and218 having independent logical addressable space starting from address0x00000000. A constraint placed on partitioning User Data Area 108 isthat the size of the up to four General Purpose Partitions is a multipleof the Write Protects Groups.

It should be noted that the standard for the embedded MultiMediaCardspecification, version 4.4, introduces a partitioning property thatspecifies general functional and nonfunctional characteristics. Thestandard stipulates that an ‘attribute’ be set in a dedicated registerto give additional features on the partitions. With the ‘attribute’ set,User Data Area 208 may be partitioned to obtain an Enhanced User DataArea (EUDA) 210. However, the configurability is limited in the standardto the number of general purpose partitions and the size of eachpartition.

The MultiMediaCard specification, version 4.4, introduces thepossibility of having portions of memory with a different ‘attribute’(enhanced) set. Configuring some of the partitions with the particular‘attribute’ connotes that some of the addressable space may havedifferent features in terms of performances or reliability,differentiating the available space to fit different usage models in thesame device. Usage models may use the software layers, with access tothe nonvolatile media, to partition the code and the application inseparated memory areas.

Specifically, if the ENH_ATTRIBUTE_ENH bit in the Extended CSD Register(not shown) is set, then the device supports the attribute by default inBoot 202, 204 and RPMB 206 areas, whereas the host may configure theGeneral Purpose Partitions or the sub-area EUDA 210 in the User DataArea 208 to support the same attribute.

In accordance with the present invention, by including a Phase-ChangeMemory (PCM) in the embedded MultiMediaCard it is possible to map theportions of memory with the ‘attribute’ enhanced set to the Phase-ChangeMemory Array, while mapping portions of the array without the‘attribute’ enhanced set to NAND Array. Therefore General Purposepartitions 212, 214, 216, and 218 with the ‘attribute’ enhanced set andthe EUDA are mapped to the Phase-Change Memory Array. In an alternativeembodiment, General Purpose partitions 212, 214, 216, and 218 with the‘attribute’ enhanced set are mapped to the Phase-Change Memory Array,while the EUDA is mapped to the NAND array configured as Enhanced.

FIG. 3 illustrates an architecture having an external Memory ControllerUnit (MCU) 302 interconnected to a nonvolatile managed memory 304through the e-MMC bus 306. This embodiment includes hybrid memorytechnologies of a Multi-Level Cell NAND Flash 310 and a Phase-ChangeMemory (PCM) storage 314. The e-MMC bus interface includes a clocksignal (CLK) that synchronizes bus transfers; a command signal (CMD)that sends commands to the device on a bidirectional command channel andresponses from the device back to the host; and bidirectional datasignals (OAT [7:0]). The data signals may be configured for a singlebit, 4-bits, or 8-bit data transfers.

With this shared bus architecture Memory Controller Unit (MCU) 302 usese-MMC bus 306 to communicate with the two different nonvolatile memorytechnologies. The figure shows that e-MMC interface 308 is coupled toMLC NAND Flash 310 and e-MMC interface 312 is coupled to Phase-ChangeMemory (PCM) 114. Using this architecture MCU 302 may considernonvolatile managed memory 304 as a ‘black box’. In other words, e-MMCinterface 308 and e-MMC interface 312 both share MMC bus 306 and thefunctionality embedded within the abstracted logical interface blockshides the actual storage media used to retain data and information.

The memory combination that includes NAND Flash 310 fulfills therequirements having reference to pure mass storage applications whilethe PCM storage 314 addresses read intensive applications such as, forexample, “demand paging” for code storage and execution. The PCMcharacteristics allow increased performances in terms of random readaccess latencies and provide higher reliability.

It should be pointed out that the combination also differentiates thememory portions in which the attribute property may be set. Incommunicating using e-MMC bus 306, both e-MMC interface 308 and e-MMCinterface 312 have well identified roles in their transactions with MCU302. Briefly referring to FIG. 1, e-MMC interface 308 services allrequests to access the User Data Area 208, the Enhanced User Data Area210 and all the General Purpose Partitions whose ‘attribute’ parameteris not set.

Thus, when managed memory 304 receives a command, the rule that isfollowed is that the e-MMC interface 308 controller is ‘aware’ of theexistence of the e-MMC interface 312 controller, but the opposite is nottrue, i.e., the e-MMC interface 312 controller is not aware of the e-MMCinterface 308 controller. Again, e-MMC interface 308 is responsible formanaging those commands and modes that involve an access to the EnhancedAreas, the User Data Area 208, and all those General Purpose Partitionswhose attributes are not set.

E-MMC interface 308 controller includes a device registers managementblock 320 and e-MMC interface 312 includes a registers management block340 to track the memory partitions which may be enabled in order to mapthe memory partitions. In general, registers management block 320 andregisters management block 340 store information about nonvolatilemanaged memory 304, information about the functionalities supported inthe device, and information used to configure the operating modes andthe functionalities themselves. The two controllers also have thecapability of disabling certain actions during the execution ofcommands.

A SWITCH command issued by MCU 306 modifies fields of the Extended CSDRegister (not shown in the figure) to configure parameters ofpartitions. Only a partition size and an attribute of up to four GeneralPurpose Partitions and an Enhanced User Data Sub Area may be chosen bythe host. If the memory portion selected by the host to configure is not‘enhanced’, then e-MMC interface 308 configures itself according to therequest.

However, in accordance with the present invention that uses PCM as thenonvolatile memory in the embedded MultiMediaCard in a managed memoryenvironment, reconfiguring the partitioning may be done during thedevice lifecycle since there is no degradation of the storage media dueto the reconfiguration process. This has particular relevance forsystems that re-organize the non-volatile memory area for bug fixing,software updates, etc.

When MCU 306 issues the SWITCH command, a register 322 inhibits aresponse in e-MMC interface 312 while e-MMC interface 308 is in chargeof generating the response towards the host application. If the SWITCHcommand is sent to set up the General Purpose Partitions with theenhanced attribute selected or the Enhanced User Data Area, then thee-MMC interface 312 configures PCM 314 to contain these partitions. Inan alternative embodiment this area may be derived from the e-MMCinterface 308 whose MLC NAND Flash may be configured partially as an SLCdevice.

The SWITCH command may select a configured partition, and in this case,the e-MMC interface 308 is the owner of the response. If the selectedpartition is a ‘default’ partition, then e-MMC interface 308 configuresitself to manage the incoming commands. On the other hand, if the hostwants to select an ‘enhanced’ partition then e-MMC interface 312configures itself. The e-MMC interface 308 remains in charge of replyingto MCU 302 so it stores parameters related to the ‘enhanced’ partitionsin order to manage possible error conditions. If the selected partitiondoes not exist then e-MMC interface 308 generates an error in theresponse to the host.

Two conditions may be distinguished when accessing a partition derivedin e-MMC interface 308 or a partition derived in e-MMC interface 312. Inthe first case, e-MMC interface 308 replies to MCU 302 and manages allof the embedded operations to service the command while e-MMC interface312 is in the idle mode. In the second case, if the command refers tothe e-MMC interface 312 then this interface replies to the host andmanages the internal operations to service the command. In thissituation where e-MMC interface 312 is in charge, the e-MMC interface308 is in a power saving mode, i.e., a standby mode, in order tominimize power consumption and efficiently allow random accesses to thememory system.

If MCU 302 accesses Main User Data Area 208 then e-MMC interface 308executes the command while e-MMC interface 312 is inhibited fromproviding a reply. If MCU 302 issues a device register SET/GET command,the e-MMC interface 308 manages these commands while the e-MMC interface312 does not provide a reply. If MCU 302 provides an initializationcommand sequence, then the e-MMC interface 308 becomes the owner of thecommand response. During the initialization phase, e-MMC interface 308executes a series of operations to properly set up the device firmwarefor the NAND Data Management. However, both e-MMC interface 308 ande-MMC interface 312 execute the corresponding state transitions in orderto be aligned and ready for the execution of the other incomingcommands. For state transitions that are induced by the MCU 302 thatinvolve the sleep state, the inactive state, etc., both devices executethe requested state transitions but only the e-MMC interface 308 repliesto the host.

FIG. 4 illustrates an architecture that includes command-responsetransitions managed by the e-MMC interface 408 connected to MCU 302through eMMC bus 306. The commands coming from the host side are visibleto e-MMC interface 412 through a connection between e-MMC interface 408and e-MMC interface 412. This connection allows commands and data to bereceived and data to be sent as requested by the host. E-MMC interface412 manages the commands referencing the partitions set up in device404.

In this architecture the memory organization allows e-MMC interface 412to handle the two boot areas, i.e., boot 202, 204, and the RPMB area,i.e., RPWB 206 (see FIG. 2). The e-MMC interface 408 handles up to fourGeneral Purpose Partitions if the partition has the ‘enhanced’ attributereset or e-MMC interface 412 handles the partitioning if the partitionhas the ‘enhanced’ attribute set. The User Data Area 208 is handled bye-MMC interface 408. The Enhanced User Data Area, i.e., EUDA 210, ishandled by e-MMC interface 408 if it is implemented by a MLC NAND Flash310 settable as SLC, otherwise it is handled by e-MMC interface 412.

FIG. 5 illustrates a multi-dice architecture having one e-MMC controller506 responsible for communicating with the host MCU 302 using the MMCprotocol and e-MMC bus 306. The e-MMC controller 506 communicates on thememory side with the differing memory technologies of MLC NAND Flash 310and Phase Change Memory 314. The e-MMC controller 506 manages thelogical memory partitioning and the enhanced default differentiation.For instance, the two boot areas and the RPMB area (boot 202, 204 andRPMB 206) are partitioned in the PCM STORAGE 314. Up to four GeneralPurpose Partitions (GP 212, 214, 216, and 218) may be partitioned in MLCNAND Flash 310 if the partition has the ‘enhanced’ attribute set or inPCM STORAGE 314 if the partition has the ‘enhanced’ attribute reset. TheUser Data Area 208 may be partitioned in MLC NAND Flash 310. TheEnhanced User Data Area (EUDA 210) may be partitioned in MLC NAND Flash310 if it is implemented by a technology settable as SLC, otherwise,EUDA 210 is partitioned in PCM STORAGE 314.

By now it should be apparent that embodiments of the present inventionallow increased memory storage efficiencies by using PCM in combinationwith NAND Flash. Since there are no dependencies on the underlyingtechnology when PCM is used in a managed memory system, variousarchitectures using controllers with different memory technologies canspeed up the configuration timing. This flexible partition-managementsystem can offer improved performance and endurance. The configurabilityprovided to the PCM memory device allows different usage models andadaptive changes to the usage models themselves during the systemlifecycle.

While certain features of the invention have been illustrated anddescribed herein, many modifications, substitutions, changes, andequivalents will now occur to those skilled in the art. It is,therefore, to be understood that the appended claims are intended tocover all such modifications and changes as fall within the true spiritof the invention.

What is claimed is:
 1. A method, comprising: managing commands through a first interface controller to mapped portions of a first memory not having an attribute enhanced set; mapping portions of a second memory having the attribute enhanced set through a second interface controller; configuring the first interface controller to be aware of the existence of the second interface controller; and configuring the second interface controller not to be aware of the first interface controller.
 2. The method of claim 1, further comprising tracking memory partitions that are enabled to map the memory partitions in the first memory or the second memory.
 3. The method of claim 2, further comprising storing indications of the tracking within a register management block located in each of the first interface controller and the second interface controller.
 4. The method of claim 1, further comprising executing state transitions to reach an inactive state during a power management mode in both the first interface controller and the second interface controller.
 5. The method of claim 1, further comprising: inhibiting responses to a host from the second interface controller; and generating the responses to the host from the first interface controller.
 6. The method of claim 1, further comprising abstracting a type of memory used to form the first memory and the second memory from a host.
 7. The method of claim 1, further comprising servicing all requests for data from a host through the first memory controller.
 8. The method of claim 1, further comprising, based on a request from a host, configuring, by the first interface controller, portions of the first memory to include the attribute enhanced set.
 9. The method of claim 1, further comprising providing responses to a host from the second interface controller when the first interface controller is in a power saving mode and requests have been sent from the host to the first interface controller.
 10. A method, comprising: managing commands through a first interface controller to mapped portions of a first non-volatile memory, the first memory not including an attribute enhanced set; managing commands through a second interface controller to mapped portions of a second non-volatile memory, the second memory including an attribute enhanced set; inhibiting responses to a host from the second interface controller; and generating the responses to the host from the first interface controller.
 11. The method of claim 10, wherein the first memory comprises a NAND flash memory and the second memory comprises a Phase-Change Memory (PCM).
 12. The method of claim 10, further comprising managing command-response transitions between a host and either the first interface controller or the second interface controller through the first interface controller.
 13. The method of claim 10, further comprising directing commands coming from a host to the second interface controller through the first interface controller.
 14. The method of claim 10, further comprising communicating commands coming from a host to the first interface controller and to the second interface controller using a common bus.
 15. A method, comprising: managing commands through a first interface controller to mapped portions of a first memory without an attribute enhanced set, the first memory comprising NAND flash; and mapping portions of a second memory with the attribute enhanced set through a second interface controller, the second memory comprising Phase-Change Memory (PCM), the first memory and the second memory forming portions of an embedded multi-media card (e-MMC) device; and providing responses to a host from the second interface controller when the first interface controller is in a power saving mode and requests have been sent from the host to the first interface controller.
 16. The method of claim 15, further comprising providing responses to a host from the first memory or the second memory through only the first interface controller.
 17. The method of claim 15, further comprising receiving data from a host and sending data to the host from the second memory through the second interface controller as requested by the host.
 18. The method of claim 15, further comprising partitioning the second memory using the second interface controller.
 19. The method of claim 15, further comprising differentiating memory portions in the second memory to provide differing usage models within the different memory portions of the e-MMC memory device.
 20. A method, comprising: managing commands through a first interface controller to mapped portions of a first memory not having an attribute enhanced set; mapping portions of a second memory having the attribute enhanced set through a second interface controller; inhibiting responses to a host from the second interface controller; and generating the responses to the host from the first interface controller.
 21. A method, comprising: managing commands through a first interface controller to mapped portions of a first memory not having an attribute enhanced set; mapping portions of a second memory having the attribute enhanced set through a second interface controller; and providing responses to a host from the second interface controller when the first interface controller is in a power saving mode and requests have been sent from the host to the first interface controller. 